Adverse pregnancy outcomes increase a woman's risk of future medical morbidities and place her infant at risk of developmental, neurological and respiratory abnormalities, as well as increased mortality. Despite the investigation of the various behavioral and psychosocial contributors a large portion of the variance in the pregnancy course remains unexplained. A growing literature shows that sleep disruption is associated with increased medical morbidity. It is widely accepted that pregnancy is associated with the disruption of sleep (3- 5). Despite this evidence, the nature and extent of this disruption remains to be determined. Recent attention has focused on evidence that systemic inflammation is involved in the pathogenesis of pregnancy complications (23). Thus, it is reasonable to propose a conceptual model where pathological disruption of sleep during early pregnancy results in systemic inflammation that contributes to risk of pregnancy complications. Likewise, it is also reasonable to propose that increased systemic inflammation contributes to increased sleep disruption observed during early pregnancy thereby contributing to increased risk of pregnancy complications. In the current proposal, we propose the first longitudinal examination of this pathophysiologic and bi-directional pathway that may contribute to risk of pregnancy complications. The following aims will be addressed: Aim 1. Characterize sleep disturbances in both complicated and uncomplicated pregnancies. Aim 2. Examine the relationship between sleep and circulating inflammatory markers during early pregnancy .Aim 3. Explore the association between sleep-related increases in proinflammatory markers and pregnancy complications. In order to answer these research questions a cohort of 400 women will be seen around 10 weeks gestation and seen twice more at ~14 weeks and ~18 weeks gestation. Participants will complete a sleep diary and wear an actigraph watch for a 2-week period. At the end of each 2-week period, participants will complete a battery of questionnaires, then have blood and physical information collected. Descriptive statistics will be used for Aim 1. A nested case-control design will be used to analyze the independent and djmamic effects of sleep and inflammation on the risk of pregnancy complications (Aims 2 and 3).